c-peptide and Angina-Pectoris

In the IMMEDIATE Trial, intravenous glucose-insulin-potassium (GIK) was started as early as possible for patients with suspected acute coronary syndrome by ambulance paramedics in communities. In the IMMEDIATE Biological Mechanism Cohort substudy, reported here, we investigated potential modes of GIK action on specific circulating metabolic components. Specific attention was given to suppression of circulating oxygen-wasting free fatty acids (FFAs) that had been posed as part of the early GIK action related to averting cardiac arrest.. We analyzed the changes in plasma levels of FFA, glucose, C-peptide, and the homeostasis model assessment (HOMA) index.. With GIK, there was rapid suppression of FFA levels with estimated levels for GIK and placebo groups after 2 hours of treatment of 480 and 781 μmol/L (P<.0001), even while patterns of FFA saturation remained unchanged. There were no significant changes in the HOMA index in the GIK or placebo groups (HOMA index: placebo 10.93, GIK 12.99; P = .07), suggesting that GIK infusions were not countered by insulin resistance. Also, neither placebo nor GIK altered endogenous insulin secretion as reflected by unchanging C-peptide levels.. These mechanistic observations support the potential role of FFA suppression in very early cardioprotection by GIK. They also suggest that the IMMEDIATE Trial GIK formula is balanced with respect to its insulin and glucose composition, as it induced no endogenous insulin secretion.

Topics: Acute Coronary Syndrome; Aged; Angina Pectoris; Blood Glucose; C-Peptide; Early Medical Intervention; Electrocardiography; Emergency Medical Services; Fatty Acids, Nonesterified; Female; Glucose; Heart Arrest; Humans; Hypoglycemic Agents; Infusions, Intravenous; Insulin; Insulin Resistance; Male; Middle Aged; Non-ST Elevated Myocardial Infarction; Potassium; ST Elevation Myocardial Infarction

Patients with microvascular angina (syndrome X) may be insulin resistant. We designed a study to establish whether this is the case. 11 patients with microvascular angina were compared with 9 matched subjects with noncardiac chest pain. Patients and controls were evaluated by coronary sinus catheterisation, and by isotopic measurement of glucose turnover, indirect calorimetry, and forearm technique during a 3 h baseline period after overnight fast and during a 2 h hyperinsulinaemic euglycaemic clamp. Pace-induced increase in coronary sinus blood flow was less in patients than in controls, whereas forearm blood flow did not differ between groups. Baseline measures of glucose metabolism were normal. During the clamp, glucose production and lipolysis were equally suppressed in both groups. Mean (SE) total insulin-induced glucose uptake was significantly impaired in patients compared with controls (3.9 [0.7] vs 6.4 [0.7] mg/kg per min; p < 0.01), and insulin-stimulated glucose uptake in the forearm was significantly reduced in patients (0.88 [0.10] vs 1.6 [0.30] mmol/L; p < 0.001). Reduced oxidative and nonoxidative metabolism accounted for the defect in overall glucose uptake in patients. No correlation between changes in coronary sinus blood flow and total body glucose uptake was seen. We found that microvascular angina was associated with substantial insulin resistance. Whether this relation is causal or coincidental is as yet unsettled.

Topics: Alanine; Angina Pectoris; Basal Metabolism; Blood Glucose; C-Peptide; Chest Pain; Coronary Circulation; Energy Metabolism; Fatty Acids, Nonesterified; Female; Forearm; Glucagon; Gluconeogenesis; Glucose Clamp Technique; Growth Hormone; Humans; Insulin; Insulin Resistance; Lactates; Male; Microcirculation; Middle Aged; Regional Blood Flow; Syndrome

Glucose and insulin responses to a glucose load in 11 patients with angina attributed to microvascular coronary dysfunction were compared with those in 11 healthy subjects matched for age, sex, and body mass. Stimulated hyperinsulinaemia was demonstrated in the microvascular angina group. The findings suggest a role for increased concentrations of insulin in coronary microvascular dysfunction.

Topics: Adult; Angina Pectoris; Blood Glucose; C-Peptide; Coronary Circulation; Evaluation Studies as Topic; Female; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin; Male; Microcirculation; Middle Aged; Syndrome

Variation in insulin and C peptide levels was examined in patients with angina of new onset and chronic coronary heart disease. Insulin secretion was increased in all coronary patients, as compared to the controls, and hormonal response to additional stress was abnormal in postmyocardial infarction patients. It is demonstrated that insulin secretion is already changed at early stages of coronary disease, and the pattern of change is presented.

Topics: Adult; Angina Pectoris; C-Peptide; Chronic Disease; Coronary Disease; Humans; Insulin; Insulin Secretion; Islets of Langerhans; Male; Middle Aged; Physical Exertion; Rest